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S2000 rocker arm ratio

 
Old 11-27-2018, 05:31 PM
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Default S2000 valve train protection and rocker arm ratio questions

Anyone know the rocker arm ratio for the F20/F22 engine? To be more specific (if it matters) a 2005 s2000. So I’ve looked around and didn’t find any direct results online. Checked against a K series (K20) which is 1.75:1 I think, but the Honda part numbers do not coincide. I am interested because I do not want to overload my rockers with my massive cams and create a catastrophic engine failure. I’ll just say my camshafts are somewhere in the Skunk2 S2 and S3 cams range ( they’re custom made). I would like to re-verify more info on these cams before I give out more specs and numbers as far as duration and lift.

Secondly and probably more importantly, who would know how to calculate a value that would tell me if I am safe or not. I could just call it a day and order Ferrea rocker arm set but, I don’t want to lose low end torque and if I can save 1k that would be nice yeah? That 1k can go towards a turbo for my MkIV Supra.

Last edited by AP2SSM; 11-27-2018 at 05:46 PM.
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Old 12-03-2018, 11:39 AM
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Using the power of deduction, I would not worry about 'overloading' your rockers. 4Piston has a road race (read: meant to be used for extended durations) that has .595" of lift on the intake cam. There are multiple people who have used this grind on their S2000 with OEM rockers. At least one was on this site. Those cams also have more lift than is advertised for the Skunk2 Ultra 3s for the K series.

What I would pay attention to is the rocker clearance on the exhaust cam. Sometimes you will need to clearance the rockers on the exhaust side to fit large Primary/Secondary lobes or large hi cam lobes.
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Old 12-04-2018, 03:26 PM
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Originally Posted by awhit17 View Post
Using the power of deduction, I would not worry about 'overloading' your rockers. 4Piston has a road race (read: meant to be used for extended durations) that has .595" of lift on the intake cam. There are multiple people who have used this grind on their S2000 with OEM rockers. At least one was on this site. Those cams also have more lift than is advertised for the Skunk2 Ultra 3s for the K series.

What I would pay attention to is the rocker clearance on the exhaust cam. Sometimes you will need to clearance the rockers on the exhaust side to fit large Primary/Secondary lobes or large hi cam lobes.
I have clearanced the rockers already because they have left their mark....Wish I would’ve known at the time of initial install but they’re good now. Only the exhaust cam was needing to be clearanced though. I have .5175” lift on exhaust and .540” on the intake. My intake cam is giving me a headache because it has 10 degrees more duration than advertised. I am in it with very low V2V clearance. That’s my current battle. I am glad to know that the stock rockers are good enough. Wish I can go Ferrea but I can’t afford to lose the low end. If Ferrea made vtec functioning rockers like they do the non vtec rockers I’d get them for sure.
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